Treatment of copper ores.



A. A. LOCKWOGD.

TREATMENT oF COPPER 0R53.

v APPLICATION FILED IAN. 20.19I7. Lg

Patented 00T. 29, 1918.

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tE @TAMS i TENT ALFRED ANDREW LOCKWQOD, vOIE FOREST HILL, ENGLAND.

TREATMENT 0F COPPER (IRES.

messes.

Application filed January 20, 1917.

To all whom t may concern:

Be lit known that I, ALFRED ANDREW- Hill, in thecounty of Surrey,England, have invented a new and useful Improvement in .the Trement ofCopper Ores, ot which the follovvid'` isaspeciiication.

This.,1nvention relates to a process by Which copper may be precipitateddirectly from a pulped ore Without ltration.

According to my invention l lead copper pulp from a preparatory vessel,provided with agitating means, into a precipitating Vessel containingdepending electrodes, and pass a current through the acid pulp kept insuspension by a jet of air, means being also provided for leading backthe residue of pulp to the preparatory vessel, afterv the electrolyticoperation.

The cathodes Which I prefer to employ consist of iron plates coated Withan easily removable skin of copper.V The copper skin is rendered easilyremovable by rst coating the plates with a layer of carbon (which termis intended to include graphite, or a carbonaceous material such as tar)and then depositing a copper coating upon the plates in any convenientmanner.

l As, moreover, carbon coated iron cathodes during electrolysis of avpulped copper ore become quickly coated With a copper skin, the cathodeplates may in the first stages of the electrolysis consist of ironplates coated with tar or other adhesive carbonaceous material, or withgraphite. lVhen a graphite coated iron plate 1s employed the graphitemust be made to adhere to the plate by some adhesive material such asvarnish or tar.

The finelyground ore previously mixed with water or with an acidleaching solution (in either case so as to produce an acid pulp) is ledinto an open vessel having a series of anodes which may be of lead. and

a series of the special cathodes hung` from supports at the top, and-alow tension current is passed between them. The cur rent employed willnecessarily depend upon the re used. With a roasted sulid ore, in theform of a pulp. containing 5% 0f free HZSO,y at the time the same entersthe electrolytic vat, have employed a current of aboutJ 2 volts, andabout .25 ampere's per Square foot of cathode area. Withother ll'atcnted@ein 2:9, Mild.

Serial No. MBATQ.

ores, larger or smaller amounts of acid, and higher or lower currentdensitities, can be used.

-The series of anodes and cathodes are so arranged that only a smallinterval (about one inch) is left between each anode and cathode for thepassage ot the pulp.

In some cases the ore may contain a sufcient quantity of acid radicalfor example S04, but if it does not there is introduced into the pulpeither before it is led into the precipitating vessel or when it is inthe vessel, either at the commencement of the electrolysis or during theprogress thereof, acid as required.

The invention is illustrated in the accom# panying drawings, in whichFigure l is a side elevation of the plant and Fig. 2 is a plan of theprecipitating vessel.

In the drawings o: is the open precipitating vessel with dependingelectrodes al and an air inlet pipe a2 for maintaining the ore insuspension.

is a vessel containing pulp which fiows through a pipe c into the vesselo and from thence is pumped back tothe top ot the vessel through a piped.

c is a pipe through which air is delivered for maintaining the ore insuspension.

The cathode which l prefer to employ in the process, is constructed asfollows 'lhe iron plates are dipped into boiling tar and then coveredwith powdered graph"- ite, these ol'ierations being repeated as manytimes as is necessary, and in some cases there is deposited upon thegraphite coating a skin of copper, or a skin ot' copper is depositedupon the tarred plate, omitting the graphite.

(lare should be taken that the coating of graphite and they copper skinshould be continuous and free from air bubbles.

At the conclusion oi' the electrolysis the copper deposited Vupon 'theeathodes may be readily removed by warming them and then stripping ofilthe copper.

With electrodes thus prepared the diff-- cllltv that. is sometimes metwith in the treatment of copper ores containing iran where the eathodesare apt to be attached by ferrie and ferrous oxids produced durM ingelectrolysis is not experienced.

The. agitation of the acid pulp in the vessel b aids solution ci' apartAof the rcopper content of the ore, until. the iifpior contains lil@aeration. rlhe pulp, Without filtration, Hows to the electrolytic vat a,and in this vessel the current causes the-deposition of copper on thecathodes, which acid is formed at the 'anodes This acid, in its nascentstate, is

highly active, and at once attacks copper in the suspended ore,dissolving a part of the saine, forming copper salts which may beelectrolyzed. r.lhis'action continues until the pulp is passed back tothe vessel b, where the returned pulp mixes with the other pulp therein,the acid thus coming into contact with a less completely leached orethan that returned in the pulp from vessel a. This f-ree acid will actupon umore of the copper ore in the pulpin vessel b. During the en-4tire cyclic passage of the ore from @through c, @pump and d back to b,there is tio filtering step, and no sedimenting step, the purpose beingto maintain an eti'ective suspension of the ore particles 1n theleachlng liquor, throughout the process. Illhe circulation is continueduntil the copper content ot' the ore under treatment falls to a very lowligure, practically no copper being left in the treated ore. A

For a more complete explanation, it may be stated that with sulfid ores,it is advisable to roast the ore, so that the copper is largely in theform of sulfate, and the iron in the form ot insoluble oxid. Carbonateores may sometimes be advantageously roasted, but this is usuallyunnecessary. The vesselI may be lled about half to two-thirds full oftine orc, and an acid liquor, e. g., diluted sulfuric acid added tonearly fill the vessel. The air blast is then introduced at c, until afairly complete mixture ensues, and the liquid pulp then allowed to passto the vessel a, air being introduced at a', and the pump started. Theamount of acid in the liquor added should be suiiicient to leave thepulp acid. The liquor fiowing through fl into is, of course, morestrongly acid than the liquor flowing out through '0.

W hat claim is 1. A process ot electro-depositing copper which comprisesiirst forming a bulk of an cyclic process.

acid pulp containing copper ore material in a liquid, agitating 'andaerating the said pulp, by air injected thereinto, leading pulp carryingmatter in suspension therein into an electrolytic vessel and passing anelectro; lytic current from aninsoluble anode copper ores whichcomprises producing an4 acidore pulp"by aerating and agitating a bulk ofcopper ore material with a suitable aqueous liquid, continuing theagitation by aeration of the pulp While withdrawing a consta-nt currentof said acid ore pulp to an electrolytic bath having vertical insolubleelectrodes therein, agitating the pulp in said electrolytic bath by thetintroduction .of air at the lower part thereof, While passing anelectric current throughpsaid bath to deposit copper, and continuouslypassing the treated pulp back from said electrolytic bath to said bulkof acid pulp, all without settling or tiltration of the acid pulp at anytage of the 3. A process for treating copper ores Which consists inagitating the pulped ore in a preparatory vessel, leading the agitatedpulp from this vessel into a precipitating vessel containing'dependinginsoluble anodes and iron cathodes, subjecting the pulp in theprecipitating vessel to electrolysis'whereby cop'- per is deposited atthe cathodes andesimult'- neously maintaining the pulp in a condition ofagitation therein.

4. A process for treating copper ores which consists in agitating thepulped ore in a pre-` paratory vessel, leading the agitated pulp fromthis vessel into a precipitating vessel containing depending insolubleanodes and iron cathodes, subjecting the pulp in the precipitatingvessel to the action ot an electricV current and simultaneouslymaintaining the same in suspension therein.-

ALFRED ANDREW LOCKWO'OD.

